Single photon emission computed tomography (SPECT) with 99mTc-HMPAO was used to image 26 patients with dementia of the Alzheimer type (DAT) and 10 healthy controls. Regional cerebral blood flow (rCBF) data indicated a relative sparing of the occipital regions in DAT. Normalisation to occipital flow illustrated highly significant CBF deficits in a number of cortical regions, particularly in the left and right posterior-temporal cortex in DAT compared to controls. The cognitive performance of DAT patients was measured using a clinical cognitive assessment procedure (CAMCOG) and numerous correlations between these scores and rCBF were obtained. The implications and value of this investigative technique are discussed.

Elliptical Fourier functions (EFF) were generated for the boundary outline of the mandibular form in 24 non-orthodontic growth study subjects at 9, 11, 13, and 15 years of age. The mean residual fit (observed versus predicted points) of the mandibular form was 0.11 mm, with a range from 0.09 to 0.14 mm, suggesting an accurate fit. The mean plot for each of the four age groups was area standardized and superimposed on the centroid. Shape changes in males and females were found to be similar. No significant shape changes were found between 9 and 11 years. Shape changes were observed in the lower incisor area, the mental region, the body of the mandible, and the gonial angle area between 11 and 15 years. These changes coincided with the onset of the pubertal growth spurt.

Objectives: (1) To develop a method of manipulating bioelectrical impedance (BIA) that gives indices of lean and fat adjusted for body size, using a large normative cohort of children. (2) To assess the discriminant validity of the method in a group of children likely to have abnormal body composition. Design: Two prospective cohort studies. Setting: Normative data: Avon Longitudinal Study of Parents and Children (ALSPAC), population based cohort; proof of concept study: tertiary feeding clinic and special needs schools. Subjects: Normative data: 7576 children measured aged between 7.25 and 8.25 (mean 7.5) (s.d. ¼ 0.2) years; proof of concept study: 29 children with either major neurodisability or receiving artificial feeding, or both, mean age 7.6 (s.d. ¼ 2) years. Measures: Leg-to-leg (Z T ) and arm-to-leg (Z B ) BIA, weight and height. Total body water (TBW) was estimated from the resistance index (RI ¼ height 2 /Z), and fat-free mass was linearly related to TBW. Fat mass was obtained by subtracting fat-free mass from total weight. Fat-free mass was log-transformed and the reciprocal transform was taken for fat mass to satisfy parametric model assumptions. Lean and fat mass were then adjusted for height and age using multiple linear regression models. The resulting standardized residuals gave the lean index and fat index, respectively. Results: In the normative cohort, the lean index was higher and fat index lower in boys. The lean index rose steeply to the middle of the normal range of body mass index (BMI) and then slowly for higher BMI values, whereas the fat index rose linearly through and above the normal range. In the proof of concept study, the children as a group had low lean indices (mean (s.d.) À1.5 (1.7)) with average fat indices ( þ 0.21 (2.0)) despite relatively low BMI standard deviation scores (À0.60 (2.3)), but for any given BMI, individual children had extremely wide ranges of fat indices. The lean index proved more stable and repeatable than BMI. Conclusions: This clinical method of handling BIA reveals important variations in nutritional status that would not be detected using anthropometry alone. BIA used in this way would allow more accurate assessment of energy sufficiency in children with neurodisability and may provide a more valid identification of children at risk of underweight or obesity in field and clinical settings.

Summary: Statistical issues in the analysis of neuroim ages are reviewed, These include biological questions of interest, basic problems of measurement and experimen tal design, normalisation, standardisation and transforma-

SummaryObjectivesTo investigate whether high weight in infancy predicts obesity in childhood.MethodData from two UK cohorts (Newcastle Growth and Development N = 795, Gateshead Millennium N = 393) and one Finnish (Tampere N = 1262) were combined. Z scores of weight at 3 and 12 months and body mass index (BMI) at 5 and 8 years were categorized as raised/overweight (1 to <2 SD) or high/obese (≥2 SD).ResultsThe majority of infants with raised or high weight at birth tended to revert to normal by 3 months and to track in the same category from 3 to 12 months. Although infants with high weight were five times more likely to have BMI ≥ 2 SD at 8 years (p < 0.001), only 22% went on to have BMI ≥ 2 SD, while 64% of infants with raised weight had normal BMI at 8 years. Of children with BMI ≥ 2 SD aged 8 years, only 22% had raised weight in infancy and half had BMI ≥ 2 SD for the first time at that age.ConclusionsInfants with raised weight in infancy tend to remain so, but most children who go on to have BMI ≥ 2 SD were not unusually heavy infants and the majority of infants with high weight reverted to overweight or normal weight in childhood.